Any modifications that weren't fitted at the factory unfortunately do need to be declared; in the case of non-performance enhancing modifications, they can alter the look of the car (eg into a different line) and/or increase the desirability of the car, so you have to declare everything otherwise they'd unfortunately be well within their rights to void or reduce cover

I asked LV if these changes using BMW original parts altered the quote and they say NO.
These are "replacements like for like".
PS) I should mention BMW are supplying and fitting Black Tips and Grills and Performance mats to mine.